Cartesian coordinate

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A member of the set of numbers that locates a point in a Cartesian coordinate system.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun geometry The coordinates of a point measured from an origin along a horizontal axis from left to right (the x-axis) and along a vertical axis from bottom to top (the y-axis). This can be extended to three-dimensions by the z-axis perpendicular to the x- and y-axes.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun one of the coordinates in a system of coordinates that locates a point on a plane or in space by its distance from two lines or three planes respectively; the two lines or the intersections of the three planes are the coordinate axes